1. RADIOLOGICAL IMAGING:
Plain Radiography.
Ultrasonography (US).
Computed Tomography (CT).
Magnetic Resonance Imaging(MRI).

2. The hip joint is located where the thigh bone (femur) meets
the pelvic bone. It is a ball and socket joint. The upper end of
the femur is formed into a round ball (the head of the femur).
A cavity in the pelvic bone forms the socket (acetabulum). The
ball is normally held in the socket by very powerful ligaments
that form a complete sleeve around the joint (the joint
capsule). The capsule has a delicate lining (the synovium). The
head of the femur is covered with a layer of smooth cartilage
which is a fairly soft, white substance about 1/8 inch thick.
The socket is also lined with cartilage (also about 1/8 inch
thick). The cartilage cushions the joint, and allows the bones
to move on each other with very little friction. An x-ray of the
hip joint usually shows a space between the ball and the
socket because the cartilage does not show up on x-rays. In
the normal hip this joint space is approximately 1/4 inch wide
and fairly even in outline.

3. Ligaments
The ligaments of the hip joint act to increase stability. They can be divided into
two groups – intracapsular and extracapsular.
Intracapsular
The only intracapsular ligament is the ligament of head of femur. It is a relatively small
ligament that runs from the acetabular fossa to the fovea of the femur. It encloses a
branch of the oburator artery, which comprises a small proportion of the hip joint blood.
Extracapsular
There are three extracapsular ligaments. They are continuous with the outer
surface of the hip joint capsule.
Iliofemoral: Located anteriorly. It originates from the ilium, immediately inferior to
the anterior inferior iliac spine. The ligament attaches to the intertrochanteric line
in two places, giving the ligament a Y shaped appearance. It prevents
hyperextension of the hip joint.
Pubofemoral: Located anteriorly and inferiorly. It attaches at the pelvis to the
iliopubic eminance and obturator membrane, and then blends with the articular
capsule. It prevents excessive abduction and extension.
Ischiofemoral: Located posteriorly. It originates from the ischium of the pelvis and
attaches to the greater trochanter of the femur. It prevents excessive extension of
the femur at the hip joint.

4. Neurovascular Structures.
Vascular supply to the hip joint is achieved via the medial and
lateral circumflex femoral arteries, and the artery to head of
femur.
The circumflex arteries are branches of the profunda femoris
artery. They anastamose at the base of the femoral neck to form
a ring, from which smaller arteries arise to the supply the joint
itself.
The medial circumflex femoral artery is responsible for the
majority of the arterial supply (the lateral circumflex femoral
artery has to penetrate through the thick iliofemoral ligament to
reach the hip joint). Damage to the medial circumflex femoral
artery can result in avascular necrosis of the femoral head.
The hip joint is innervated by the femoral nerve, obturator nerve,
superior gluteal nerve, and nerve to quadratus femoris.

5. 1. Lateral part of the sacrum
2. Gas in colon
3. Ilium
4. Sacroiliac joint
5. Ischial spine
6. Superior ramus of pubis
7. Inferior ramus of pubis
8. Ischial tuberosity
9. Obturator foramen
10. Intertrochanteric crest
11. Pubic symphysis
12. Pubic tubercle
13. Lesser trochanter
14. Neck of femur
15. Greater trochanter
16. Head of femur
17. Acetabular fossa
18. Anterior inferior iliac spine
19. Anterior superior iliac spine
20. Posterior inferior iliac spine
21. Posterior superior iliac spine
22. Iliac crest

6. 1. Anterior superior iliac spine
2. Ilium
3. Anterior inferior iliac spine
4. Pelvic brim
5. Acetabular fossa
6. Head of femur
7. Fovea
8. Superior ramus of pubis
9. Obturator foramen
10. Inferior ramus of pubis
11. Pubic symphysis
12. Ischium
13. Lesser trochanter
14. Intertrochanteric crest
15. Greater trochanter
16. Neck of femur

7. 1. Greater trochanter
2. Intertrochanteric crest
3. Lesser trochanter
4. Neck of femur
5. Head of femur
6. Acetabular fossa
7. Superior ramus of pubis
8. Obturator foramen
9. Inferior ramus of pubis
10. Ischium

8. Pelvis anatomy - Normal AP
The 2 hemi-pelvis bones
and the sacrum form a
bone ring bound posteriorly
by the sacroiliac joints and
anteriorly by the pubic
symphysis
Each obturator foramen is
also formed by a ring of
bone.

9. Hemi-pelvis anatomy - Normal AP
Each hemi-pelvis bone comprises 3 bones
- the ilium (white), pubis (orange) and
ischium (blue)
The 3 bones fuse to form the acetabulum
- the pelvic portion of the hip joint
ASIS = Anterior Superior Iliac Spine =
attachment site for sartorius muscle
AIIS = Anterior Inferior Iliac Spine =
attachment site for rectus femoris muscle

10. Hip X-ray anatomy - Normal AP
Shenton's line is formed by
the medial edge of the
femoral neck and the
inferior edge of the superior
pubic ramus
Loss of contour of Shenton's
line is a sign of a fractured
neck of femur

11. Hip X-ray anatomy - Normal
Lateral
The cortex of the proximal
femur is intact.
The Lateral view is often not
so clear because those with
hip pain find the positioning
required difficult .

12. Intracapsular v extracapsular
The capsule envelopes the
femoral head and neck
Subcapital, transcervical and
basicervical fractures are
intracapsular hip injuries
Intertrochanteric and
subtrochanteric fractures do
not involve the neck of femur.

13. Pelvis anatomy - Normal AP
The 2 hemi-pelvis bones
and the sacrum form a
bone ring bound posteriorly
by the sacroiliac joints and
anteriorly by the pubic
symphysis
Each obturator foramen is
also formed by a ring of
bone.

14. Hemi-pelvis anatomy - Normal AP
Each hemi-pelvis bone comprises 3 bones
- the ilium (white), pubis (orange) and
ischium (blue)
The 3 bones fuse to form the acetabulum
- the pelvic portion of the hip joint
ASIS = Anterior Superior Iliac Spine =
attachment site for sartorius muscle
AIIS = Anterior Inferior Iliac Spine =
attachment site for rectus femoris muscle

16. A, C) US scans obtained at the
proximal tendon of the rectus
femoris (A) and at the proximal
myotendinous junction (B). (B,
D) T1-weighted MRI images
corresponding to the US scans.
US provides visualization of the
direct tendon (black arrows)
and the indirect tendon (white
arrows) of the rectus femoris.
In A, the posterior shadow cone
of the tendon is an indirect
consequence of its obliquity. At
the rectus femoris
myotendinous junction (DA), it
is inserted on to the lateral
surface of the direct tendon.
TFL: tensor fasciae latae
muscle; Sat: sartorius muscle;
IP: iliopsoas muscle; PGL: small
gluteal muscle.

17. (US images on the left): US
Sagittal scan obtained at the
direct tendon (black arrows) and
indirect tendon (white arrows) of
the rectus femoris muscle (RF).
The image on the top was
obtained by scanning at the
medial level as compared to the
image below. (MR images on the
right): T1-weighted MR image
corresponding to the US scans.
The direct tendon shows a
homogeneous and hyperechoic
appearance. Its insertion on to
the anterior-inferior iliac spine is
well visible on the US image. In
physiological conditions the
tendon is thicker just before
insertion. In B, the indirect
tendon appears hypoechoic
because of anisotropy.

18. (US images on the left): US
Sagittal scan obtained at the
direct tendon (black arrows) and
indirect tendon (white arrows) of
the rectus femoris muscle (RF).
The image on the top was
obtained by scanning at the
medial level as compared to the
image below. (MR images on the
right): T1-weighted MR image
corresponding to the US scans.
The direct tendon shows a
homogeneous and hyperechoic
appearance. Its insertion on to the
anterior-inferior iliac spine is well
visible on the US image. In
physiological conditions the
tendon is thicker just before
insertion. In B, the indirect tendon
appears hypoechoic because of
anisotropy.

19. (US images on the left): US
oblique axial scans obtained
at the femoral neck (top) and
the femoral head (below).
(MR images on the right): T1-
weighted MR images
corresponding to the US
scans. The ileofemoral
ligament appears as a
hyperechoic band (curved
arrow) in front of the femoral
neck (CF). C, D: at the femoral
head, the ligament appearing
as a fibrillar structure (white
arrow) is inserted on to the
front edge of the cup near the
anterior acetabular labrum
(arrowheads). IP: iliopsoas
muscle; Sa: sartorius muscle;
RF: rectus femoris.

20. (A, B): US scans
obtained at the
femoral vessels. (C):
T1-weighted MR
image corresponding
to the US scans. US
provides visualization
of the common
femoral artery (white
arrows), the common
femoral nerve
traveling outside the
artery (black arrows)
and the common
femoral vein inside
(empty arrow).

21. (A, C): axial US scans carried
out at the gluteus muscles and
their insertion on to the greater
trochanter. (B, D): T1-weighted
MR images corresponding to
the US scans. US provides
visualization of the gluteus
medius muscle (MG) and the
deeper located gluteus
minimus muscle (PG). The
image obtained at the level of
the tendons provides
distinction between the tendon
of the gluteus minimus muscle
(black arrow) traveling in front
of the tendon of the gluteus
medius muscle (white arrow).
Arrowhead: fasciae latae. VE =
external vastus muscle
(quadriceps muscle).

22. (US images on the left): Coronal US
scans carried out at the lateral
surface of the hip. (MR images on
the right): T1-weighted MR images
corresponding to the US scans. •
Photo, top = anterior image shows
the tendon of the gluteus minimus
muscle (black arrow) that inserts on
to the lateral surface of the greater
trochanter. Arrowhead: fasciae
latae. • Photo, mid = image
obtained at the middle third of the
greater trochanter shows the
anterior tendon of the gluteus
medius muscle (white arrow).
Arrowhead: fasciae latae. • Photo,
bottom = posterior image shows the
posterior tendon of the gluteus
medius muscle (empty arrow) which
inserts on to the apex of the greater
trochanter.

27. Osseous Anatomy
The pelvis is formed by the two innominate bones that articulate
posteriorly with the sacrum at the sacroiliac joints and anteriorly at
the pubic symphysis. Each innominate bone is composed of an ilium,
ischium, and pubis. The acetabulum is formed by the junction of
these osseous structures. The posterior acetabulum is stronger and
along with the dome comprises the weight-bearing portion of the
acetabulum. The margin of the acetabulum is surrounded by a
fibrocartilaginous labrum.
The hip is a ball and socket joint. The fibrous capsule of the hip joint
is lined with synovial membrane and the hyaline cartilage covers the
articular surfaces of the acetabulum and femoral head. There are
several important intra-articular structures that should be identified
on MR images. Ligamentum teres is a firm ligament extending from
the fovea of the femoral head to the acetabulum. The ligament
enters a small notch in the medial acetabular wall where it is
surrounded by fat.

28. Muscular Anatomy
The anatomy of the muscles acting on the pelvis, hips, and thighs in axial,
coronal, sagittal, and even oblique planes must be thoroughly understood to
interpret MR images and evaluate symptoms related to these structures. The
muscles acting on the hip joint per se are numerous. Therefore, it is simplest
to discuss them based upon their function.
The chief extensors of the hip include the gluteus maximus and posterior
portion of the adductor magnus. Extension is also accomplished to some
degree by assistance from the semimembranosus, semitendinosus, biceps
femoris, gluteus medius, and gluteus minimus The primary flexor of the hip is
the iliopsoas muscle. However, the pectineus, tensor fasciae latae, adductor
brevis, and sartorius also function in this regard. Accessory flexors include the
adductor longus, adductor magnus, gracilis, and gluteus minimus. The iliacus
and psoas muscle anatomy is important for accurate interpretation of MR
images. The bulk of the iliacus muscle run parallel to the iliopsoas tendon and
attach to the proximal femur. In some cases, a small iliacus tendon runs
parallel to the iliopsoas tendon as it attaches to the lesser trochanter. The
iliopsoas tendon is separated from the iliacus muscle and tendon by a small
amount of fatty tissue.

54. Radiographic Anatomy
The knee joint is composed of three articulations: the medial and
lateral femorotibial and patellofemoral articulations. Although they
share a common joint capsule, these articulations are often referred to
separately as the medial, lateral, and patellofemoral compartments or
joints. An anteroposterior (AP) knee radiograph shows the femoral
condyles and tibial plateaus. The medial and lateral compartment
radiolucent “joint spaces” or “cartilage spaces” should be equal with
the knee extended; asymmetry usually indicates cartilage loss,
ligamentous laxity, or both. Standing views may accentuate such
findings. A standing view with the knees slightly flexed can be even
better at demonstrating cartilage loss not evident with the knee fully
extended, because earlier and more severe cartilage loss often occurs
along the posterior weight-bearing portions of the femoral condyles.
A lateral radiograph profiles the anterior weight-bearing, mid–weight-bearing,
and posterior weight-bearing surfaces of the femoral condyles
and also reveals differences between the condyles and tibial plateaus.

59. ROLE OF ULTRASOUND
Ultrasound is essentially used for the external structures of the knee.
Ultrasound is a valuable diagnostic tool in assessing the following
indications; Muscular, tendinous and ligamentous damage (chronic
and acute) Bursitis Joint effusion Popliteal vascular pathology
Haematomas Masses such as Baker’s cysts, lipomas Classification
of a mass e.g solid, cystic, mixed Post surgical complications e.g
abscess, edema Guidance of injection, aspiration or biopsy
Relationship of normal anatomy and pathology to each other Some
boney pathology.
LIMITATIONS
It is recognised that ultrasound offers little or no diagnostic
information for internal structures such as the cruciate ligaments.
Ultrasound is complementary with other modalities, including plain
X-ray, CT, MRI and arthroscopy.

60. Transverse suprapatella region:
•RF: Rectus Femoris •VI: Vastus intermedius
•VL: Vastus Lateralis •VM: Vastus Medialis
Longitudinal suprapatella region showing the
suprapatella bursa and quadriceps tendon.

61. The infra-patellar tendon.
Transverse Infrapatellar tendon. Note how
wide it is, to then have an understanding of
the area you need to examine in longitudinal.

62. Pes Anserine tendons.
The medial collateral ligament (green) directly
overlying the medial meniscus (purple).

63. Assess the Lateral collateral ligament, Ilio-
Tibial band insertion and peripheral margins
of the lateral meniscus. Unlike the medial
side, the LCL is separated from the meniscus
by a thin issue plane.

64. Medial aspect of the popliteal fossa showing
the semimembranosis/gastrocnemius plane
Ultrasound of the Popliteal vein and
artery in transverse. Without and with
compression to exclude DVT.

65. Confirm both arterial and venous flow and exclude a popliteal artery aneurysm. If a
Popliteal aneurysm is discovered, always extend the examination to the other leg and
the abdomen. There is a risk of bilateral and high association with aortic aneurysm.

66. The knee joint joins the thigh with the leg and consists of two
articulations: one between the femur and tibia, and one between the
femur and patella.
The articular bodies of the femur are its lateral and medial condyles.
These diverge slightly distally and posteriorly, with the lateral condyle
being wider in front than at the back while the medial condyle is of more
constant width. The radius of the condyles' curvature in the sagittal plane
becomes smaller toward the back. This diminishing radius produces a
series of involute midpoints (i.e. located on a spiral). The resulting series
of transverse axes permit the sliding and rolling motion in the flexing
knee while ensuring the collateral ligaments are sufficiently lax to permit
the rotation associated with the curvature of the medial condyle about a
vertical axis.
The pair of tibial condyles are separated by the intercondylar eminence
composed of a lateral and a medial tubercle.
The patella is inserted into the thin anterior wall of the joint capsule. On
its posterior surface is a lateral and a medial articular surface, both of
which communicate with the patellar surface which unites the two
femoral condyles on the anterior side of the bone's distal end.

79. The knee is a hinge type synovial joint, which is composed of three functional
compartments: the femoropatellar articulation, consisting of the patella, or
"kneecap", and the patellar groove on the front of the femur through which it
slides; and the medial and lateral femorotibial articulations linking the femur, or
thigh bone, with the tibia, the main bone of the lower leg. The joint is bathed in
synovial fluid which is contained inside the synovial membrane called the joint
capsule. The posterolateral corner of the knee is an area that has recently been
the subject of renewed scrutiny and research.
The knee is one of the most important joints of our body. It plays an essential
role in movement related to carrying the body weight in horizontal (running and
walking) and vertical (jumps) directions.
At birth, a baby will not have a conventional knee cap, but a growth formed of
cartilage. By the time that the child is 3–5 years of age, ossification will have
replaced the cartilage with bone. Because it is the largest sesamoid bone in the
human body, the ossification process takes significantly longer.
Bursae: Numerous bursae surround the knee joint. The largest
communicative bursa is the suprapatellar bursa described above. Four
considerably smaller bursae are located on the back of the knee. Two non-communicative
bursae are located in front of the patella and below the patellar
tendon, and others are sometimes present.

80. Cartilage.
Cartilage is a thin, elastic tissue that protects the bone and makes certain that the
joint surfaces can slide easily over each other. Cartilage ensures supple knee
movement. There are two types of joint cartilage in the knees: fibrous cartilage (the
meniscus) and hyaline cartilage. Fibrous cartilage has tensile strength and can resist
pressure. Hyaline cartilage covers the surface along which the joints move. Cartilage
will wear over the years. Cartilage has a very limited capacity for self-restoration. The
newly formed tissue will generally consist of a large part of fibrous cartilage of lesser
quality than the original hyaline cartilage. As a result, new cracks and tears will form
in the cartilage over time.
Menisci
The articular disks of the knee-joint are called menisci because they only partly divide
the joint space. These two disks, the medial meniscus and the lateral meniscus, consist
of connective tissue with extensive collagen fibers containing cartilage-like cells.
Strong fibers run along the menisci from one attachment to the other, while weaker
radial fibers are interlaced with the former. The menisci are flattened at the center of
the knee joint, fused with the synovial membrane laterally, and can move over the
tibial surface. The menisci serve to protect the ends of the bones from rubbing on each
other and to effectively deepen the tibial sockets into which the femur attaches. They
also play a role in shock absorption, and may be cracked, or torn, when the knee is
forcefully rotated and/or bent.

81. Ligaments:
Intracapsular.
The knee is stabilized by a pair of cruciate ligaments. The anterior cruciate
ligament (ACL) stretches from the lateral condyle of femur to the anterior
intercondylar area. The ACL is critically important because it prevents the tibia
from being pushed too far anterior relative to the femur. It is often torn during
twisting or bending of the knee. The posterior cruciate ligament (PCL) stretches
from medial condyle of femur to the posterior intercondylar area. Injury to this
ligament is uncommon but can occur as a direct result of forced trauma to the
ligament. This ligament prevents posterior displacement of the tibia relative to
the femur.
The transverse ligament stretches from the lateral meniscus to the medial
meniscus. It passes in front of the menisci. It is divided into several strips in 10% of
cases. The two menisci are attached to each other anteriorly by the ligament. The
posterior and anterior meniscofemoral ligaments stretch from the posterior horn
of the lateral meniscus to the medial femoral condyle. They pass posteriorly
behind the posterior cruciate ligament. The posterior meniscofemoral ligament is
more commonly present (30%); both ligaments are present less often. The
meniscotibial ligaments (or "coronary") stretches from inferior edges of the
mensici to the periphery of the tibial plateaus.

82. Extracapsular.
The patellar ligament connects the patella to the tuberosity of the tibia. It is also
occasionally called the patellar tendon because there is no definite separation between
the quadriceps tendon (which surrounds the patella) and the area connecting the patella
to the tibia. This very strong ligament helps give the patella its mechanical leverage and
also functions as a cap for the condyles of the femur. Laterally and medially to the patellar
ligament the lateral and medial patellar retinacula connect fibers from the vasti lateralis
and medialis muscles to the tibia. Some fibers from the iliotibial tract radiate into the
lateral retinaculum and the medial retinaculum receives some transverse fibers arising on
the medial femoral epicondyle. The medial collateral ligament (MCL a.k.a. "tibial")
stretches from the medial epicondyle of the femur to the medial tibial condyle. It is
composed of three groups of fibers, one stretching between the two bones, and two fused
with the medial meniscus. The MCL is partly covered by the pes anserinus and the tendon
of the semimembranosus passes under it. It protects the medial side of the knee from
being bent open by a stress applied to the lateral side of the knee (a valgus force). The
lateral collateral ligament stretches from the lateral epicondyle of the femur to the head
of fibula. It is separate from both the joint capsule and the lateral meniscus. It protects the
lateral side from an inside bending force (a varus force). The anterolateral ligament (ALL)
is situated in front of the LCL. Lastly, there are two ligaments on the dorsal side of the
knee. The oblique popliteal ligament is a radiation of the tendon of the semimembranosus
on the medial side, from where it is direct laterally and proximally. The arcuate popliteal
ligament originates on the apex of the head of the fibula to stretch proximally, crosses the
tendon of the popliteus muscle, and passes into the capsule.

117. The ankle joint or “talocrural joint” is a synovial hinge joint that is
made up of the articulation of 3 bones. The 3 bones are the tibia, the
fibula and the talus. The articulations are between the talus and the tibia
and the talus and the fibula.
The “mortise” is the concaved surface formed by the tibia and fibula. The
mortise is adjustable and is controlled by the proximal and distal
tibiofibular joints. The talus articulates with this surface and allows
dorsiflexion and plantar flexion.
Most congruent joint in the body. It allows in open chain activity (non-weight
bearing), the convex talus slides posteriorly during dorsiflexion and
anteriorly during plantar flexion on the concave tibia and fibula.
In closed chain activity (weight bearing), the tibia and fibula move on the
talus. Subtalar joint:
Also known as the talocalcaneal joint. It is a triplanar, uniaxial joint which
allows 1°of freedom: supination(closed packed position) and
pronation(open).
Supination is accompanied by calcaneal inversion (calcaneovarus) and
pronation is accompanied by calcaneal eversion (calcaneovalgus).

124. Ultrasound of the ankle:
For specific indications, ultrasound (US) is an efficient and
inexpensive alternative to magnetic resonance (MR) imaging for
evaluation of the ankle. In addition to the tendons and tendon
sheaths, other ankle structures demonstrated with US include the
anterior joint space, retrocalcaneal bursa, ligaments, and plantar
fascia. Ankle US allows detection of tenosynovitis and tendinitis, as
well as partial and complete tendon tears. Joint effusions,
intraarticular bodies, ganglion cysts, ligamentous tears, and plantar
fasciitis can also be diagnosed. As pressure for cost containment
continues, demand for US of the ankle may increase given its lower
cost compared with that of MR imaging. In most cases, a focused
ankle US examination can be performed more rapidly and efficiently
than MR imaging. Familiarity with the technique of ankle US,
normal US anatomy, and the US appearances of pathologic
conditions will establish the role of US as an effective method of
imaging the ankle.

125. Peroneus longus and brevis tendons.
Transverse at the medial malleolus.
Peroneus brevis insertion onto
the base of the 5th metatarsal.

126. Calcaneo-fibular ligament Anterior Talo-fibula ligament (ATFL).

127. Normal Tibio fibula ligament. Extensor digitorum tendon

128. Longitudinal extensor hallucis longus tendon. Longitudinal Tibialis Anterior tendon.

129. Tibialis posterior, flexor Digitorum and flexor
Hallucis longus tendons (known as "Tom, Dick
& Harry"). If including the neurovascular
bundle - Tom Dick And Very Nervous Harry. Deltoid ligament

130. Normal Achilles tendon longitudinal panorama

131. The ankle joint acts like a hinge. But it's much more than a simple
hinge joint. The ankle is actually made up of several important
structures. The unique design of the ankle makes it a very stable joint.
This joint has to be stable in order to withstand 1.5 times your body
weight when you walk and up to eight times your body weight when
you run. Normal ankle function is needed to walk with a smooth and
nearly effortless gait.
The muscles, tendons, and ligaments that support the ankle joint work
together to propel the body. Conditions that disturb the normal way
the ankle works can make it difficult to do your activities without pain
or problems.
This guide will help you understand what parts make up the ankle
•Important Structures
The important structures of the ankle can be divided into several
categories. These include
•bones and joints.
•ligaments and tendons.
•Muscles.
•Nerves.
•blood vessels.

140. The ankle, or the talocrural region, is the region where the foot and the leg meet.
The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar
joint, and the Inferior tibiofibular joint. The movements produced at this joint are
dorsiflexion and plantarflexion of the foot. In common usage, the term ankle refers
exclusively to the ankle region. In medical terminology, "ankle" (without qualifiers)
can refer broadly to the region or specifically to the talocrural joint.
The main bones of the ankle region are the talus (in the foot), and the tibia and fibula
(in the leg). The talus is also called the ankle bone. The talocrural joint is a synovial
hinge joint that connects the distal ends of the tibia and fibula in the lower limb with
the proximal end of the talus. The articulation between the tibia and the talus bears
more weight than that between the smaller fibula and the talus. The bony
architecture of the ankle consists of three bones: the tibia, the fibula, and the talus.
The articular surface of the tibia is referred to as the plafond. The medial malleolus is
a bony process extending distally off the medial tibia. The distal-most aspect of the
fibula is called the lateral malleolus. Together, the malleoli, along with their
supporting ligaments, stabilize the talus underneath the tibia.
The bony arch formed by the tibial plafond and the two malleoli is referred to as the
ankle "mortise" (or talar mortise). The mortise is a rectangular socket. The ankle is
composed of three joints: the talocrural joint (also called tibiotalar joint, talar mortise,
talar joint), the subtalar joint (also called talocalcaneal), and the Inferior tibiofibular
joint. The joint surface of all bones in the ankle are covered with articular cartilage.

141. Ligaments.
The ankle joint is bound by the strong deltoid ligament and three lateral ligaments: the
anterior talofibular ligament, the posterior talofibular ligament, and the calcaneofibular
ligament.
The deltoid ligament supports the medial side of the joint, and is attached at the medial
malleolus of the tibia and connect in four places to the sustentaculum tali of the calcaneus,
calcaneonavicular ligament, the navicular tuberosity, and to the medial surface of the
talus.
The anterior and posterior talofibular ligaments support the lateral side of the joint from
the lateral malleolus of the fibula to the dorsal and ventral ends of the talus.
The calcaneofibular ligament is attached at the lateral malleolus and to the lateral surface
of the calcaneous.
Though it does not span across the ankle joint itself, the syndesmotic ligament makes an
important contribution to the stability of the ankle. This ligament spans the syndesmosis,
which is the term for the articulation between the medial aspect of the distal fibula and the
lateral aspect of the distal tibia. An isolated injury to this ligament is often called a high
ankle sprain.
The bony architecture of the ankle joint is most stable in dorsiflexion. Thus, a sprained
ankle is more likely to occur when the ankle is plantar-flexed, as ligamentous support is
more important in this position. The classic ankle sprain involves the anterior talofibular
ligament (ATFL), which is also the most commonly injured ligament during inversion
sprains. Another ligament that can be injured in a severe ankle sprain is the
calcaneofibular ligament.

179. Thank You.